Apparatus and Method for Reprocessing Lumened Instruments

ABSTRACT

Methods and apparatus for liquid, gas, and gas plasma sterilization of items. The apparatus includes two chambers and a holder to connectorlessly secure a lumened instrument such that a first portion of the lumened instrument lies in the first chamber and a second portion of the instrument lies in the second chamber, a liquid medium contained within the two chambers, and pumping means for simultaneously increasing fluid pressure within the first chamber of said container while decreasing fluid pressure within the second chamber of the container in a reciprocating fashion. The pumping means displaces at least a total internal volume of the liquid medium through the lumen for a given highest volume of a lumened instrument during a stroke.

CROSS-REFERENCE TO RELATED APPLICATION

This application is continuation of application of U.S. patentapplication Ser. No. 13/623,750, filed on Sep. 20, 2012, which is adivisional of 12/247,830, filed on Oct. 8, 2008, which is acontinuation-in-part of U.S. patent application Ser. No. 11/367,787,filed on Mar. 3, 2006, the contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to improved apparatus and methods forreprocessing items with lumens, and, more particularly, to apparatus andmethods that involve flowing a liquid through a divided chambercontaining the item to be cleaned and sterilized.

2. Description of the Related Art

The reprocessing (i.e., cleaning and decontamination) of items that comeinto contact with the bodily substances of people or animals such thatthey are substantially “substance free” (of, e.g., viruses, bacteria,detergent, sterilant, lipids, etc.) represent an immense and ongoingchallenge. This challenge has been underscored by a recent articleentitled “Widely used sterilizer under attack” (published in Jan. 21,2003 edition of the newspaper USA Today). The article describes a fataloutbreak of bacterial infection that was linked to the impropersterilization of hospital bronchoscopes. Despite the hospital's use ofone of the most popular sterilizing systems, tests performed by theCenters for Disease Control and

Prevention found bacteria on the system's water filters and in its rinsewater. This and other infection outbreaks have led to continuingcontroversy over how best to clean and sterilize used endoscopes. Thesechallenges persist to the present day.

The contaminants typically found on tubular or “lumened” medical items,such as endoscopes, are especially difficult to remove. In addition tofecal mater, loose cellular debris, blood and blood products, viruses,and bacteria, an endoscope can be coated with various hydrophobic films,such as “biofilm” material. A biofilm typically comprises cells, bothdead and alive, cell debris and extracellular polymer substances. Oncebiofilm is formed by microorganisms (including bacteria, fungi, andprotozoans), these microorganisms can colonize and replicate on theinterior surfaces of tubing, forming a protective slime layer known as a“glycocalyx” that is especially difficult to remove.

Merely soaking endoscopes in a sterilant or detergent is unacceptablesince numerous pockets exist within the tubing where the sterilant ordetergent cannot reach effectively, which leaves areas of contaminationwithin the endoscope. Moreover, with the prevalence of highly contagiousdiseases such as hepatitis B and C and Acquired Immune DeficiencySyndrome, as well as the pathogens MRSA (Methicillin-resistantStaphylococcus aureus) and Clostridium difficile, reliable sterilizationor disposal of all used medical tools seemingly becomes mandatory. Yet,while many medical instruments today are routinely cleaned, disinfected,and reused, experts in the field recently have warned that some of themore difficult to clean and sterilize medical items are putting peopleat risk. For example, the website “myendosite.com” contains scores ofrecent references involving infection and endoscopy in the news (seemyendosite.com/infection control media.htm).

Many attempts to improve sterilization apparatus and methods have beentried over the years. For example, a variety of gas sterilizationmethods has been investigated in the past. Methods using ethylene oxideand other disinfecting gases are widely used for sterilizing a widerange of items, from contact lenses to surgical instruments.

A sterilizing method must effectively kill all organisms, includingspores, without damage to the article or goods being sterilized.Moreover, before sterilization can take place, the instrument must becleaned to the FDA quantifiable validated standard of clean. Indeed, noreprocessor on the market can perform this other than the unique“push/pull reprocessors” created by the inventor and described below.

So-called “push/pull reprocessing systems” are automatic apparatusesthat include a chamber containing a baffle with one or more openingsthrough which water (or another fluid) surges in a synchronous fashionback-and-forth (hence “push/pull”) through the opening or openings inthe baffle. When soiled items, such as endoscopes and other lumenedinstruments, are placed within an opening in the baffle, fluid alsosurges upon and through them. Accordingly, a back-and-forth “scrubbingaction” is created by the surging fluid the contacts any accessiblesurface on an item, including any lumen or lumens.

For example, U.S. Pat. No. 5,711,921 by Langford discloses a medicalapparatus cleaning mechanism that includes a container having a firstchamber and a second chamber, with the container adapted to accept amedical instrument such that a first portion of the medical instrumentlies in the first chamber and a second portion of the medical instrumentlies in the second chamber. Pumping means then simultaneously increasefluid pressure within the first chamber of the container whiledecreasing fluid pressure within the second chamber until the cycle isreversed, i.e., the fluid pressure in the second chamber increases whilethe fluid pressure in the first chamber synchronously is decreased.

While the Langford apparatus is known to provide superb cleaning andsterilization, the teachings of the Langford patent appear limited tothe use of the apparatus with a single-size lumen diameter and do notspecify how to evacuate the entire lumen volume per each change in fluidflow direction (i.e., a “stroke”).

U.S. Pat. No. 6,534,002 by Lin further notes alleged shortcomings of theteachings in Langford as follows: “One significant problem with thissurging mechanism for cleaning endoscopes results from the fact thatendoscope channels often have different diameters at their oppositeends. As fluid flows from the larger-caliber end of an endoscope channelto the smaller-caliber end, particulate matter and human tissue,secretions, and excrement can become lodged in the smaller-caliber endand extremely difficult to extract. Another problem with the surgingmechanism results from the frequent change in directional flow of fluidthrough the channels of an endoscope. In cleaning an endoscope, debrismust travel a long distance, sometimes more than 150 cm, to traverse thelength of the endoscope before the debris can exit the endoscope. Insurging methods of cleaning endoscopes, some fluid, debris, and airpockets may move back and forth within the endoscope channel, but nevertravel far enough to exit the channel before the next directional shiftin flow occurs. Thus, some debris and air pockets can remain trapped inthe central portion of an endoscope channel with the surging method ofcleaning”

The main thrust of how the Lin patent proposes to deal with theseshortcomings involves generating a flow of sanitizing solution through alumened instrument in predominantly one direction, from thesmaller-caliber end to the larger-caliber end, to clean or sterilize theinner surface of the device.

However, flowing a fluid in “predominantly one direction” does notnecessarily result in better cleaning or sterilizing action; indeed,material may become trapped in complex lumened instruments (such as arestrictor valve in a colonoscope or the spring and guide wire of abiopsy forceps) if a recurring back-and-forth motion is not used todislodge it.

From the above, it can readily be seen that complex lumened medicaldevices present unique challenges. Some instruments (e.g., abronchoscope) have a main lumen of one diameter and another lumen ofsmaller diameter branching off the main lumen, presenting two resistanceratings inside the same instrument. Furthermore, various lumenedinstruments have restrictor valves inside the lumen narrowing the fluidpath in one direction. This acts as a point of blockage or increasedresistance if debris is pushed up against the restrictor. Thus, forthose devices that have different size internal lumens in the sameinstrument, as well as for those that can be 6 feet or longer in length(e.g., a colonoscope), resistance to fluid flow during cleaning andsterilization presents a difficult problem.

Accordingly, it would be desirable to provide an apparatus and methodthat carry out effective cleaning and sterilization of even complexlumened instruments quickly and thoroughly, while reducing undesirableeffects. In addition, it is desirous that the fluid flow about theexterior of a lumened instrument cause sufficient turbulence to cleanthe outside of the instrument as well.

SUMMARY OF THE INVENTION

The invention generally involves methods and apparatus for reprocessingitems with lumens. According to one aspect of the invention, a lumenedinstrument reprocessing apparatus is provided. The apparatus includestwo chambers and a holder to connectorlessly secure a lumened instrumentsuch that a first portion of the lumened instrument lies in the firstchamber and a second portion of the instrument lies in the secondchamber, a liquid medium contained within the two chambers, and pumpingmeans for simultaneously increasing fluid pressure within the firstchamber of the container while decreasing fluid pressure within thesecond chamber of said container in a reciprocating fashion. The pumpingmeans is designed to displace at a substantially constant pressure atleast a total internal volume of the liquid medium through the lumen fora given highest volume of a lumened instrument during each stroke.

According to another aspect of the invention, a method for cleaning orsterilizing a device having a lumen, an inner surface, and an outersurface, involves the steps of a) providing a “push-pull” (i.e.,back-and-forth fluid motion) reprocessor having a container including atleast one interface that divides the container into two or morechambers; b) securing one or more lumened devices in a connectorlessfashion within the interface; c) generating a flow of a fluid frominside the container through the lumen such that fluid corresponding toat least a total internal volume of the lumen is displaced therethroughduring each stroke of the reprocessor.

In another embodiment, an item is cleaned within a push/pullreprocessing apparatus, contained within sterilizable packaging, andsterilized within the reprocessing apparatus through the introduction ofa sterilant, the flow of which includes fresh or new sterilant, such assteam, at one or more times during the sterilizing cycle. Thus, a devicecan be removed from the apparatus in a sterile package, therebymaintaining post-processing sterility.

In still another embodiment, the invention includes a plasma sterilizerthat employs uncharged, highly reactive free radicals, atoms, andexcited molecules of a gas mixture to sterilize articles. According tothis aspect of the invention, a sterilizer apparatus includes a cleaningand sterilizing chamber, a plasma generating chamber/mixing tank adaptedto allow a gas mixture streaming therethrough, means for ionizing thegas mixture in the plasma generating chamber/mixing tank, and a plasmadistribution means for distributing downstream plasma gas products tothe sterilizing chamber.

A removable baffle plug of the invention is provided to allow for theplacement of different sized items within the baffle, to modulate thepressure between parts of the chamber on either side of the baffle, andto provide information about what is being placed in the chamber throughthe use of radio frequency identification devices. The plug allows flowbetween the device being held and the interface, thereby creating aturbulent flow to clean the device exterior in each direction.

In another embodiment, the pressure within both chambers of thepush-pull apparatus is kept substantially constant. For example, thepumping means is used to keep the pressure around 12.5 psi in someembodiments of the invention.

In accordance with the above methods, there is provided new and improvedapparatus for sterilizing an item.

Various other purposes and advantages of the invention will become clearfrom its description in the specification that follows. Therefore, tothe accomplishment of the objectives described above, this inventionincludes the features hereinafter fully described in the detaileddescription of the preferred embodiments, and particularly pointed outin the claims. However, such description discloses only some of thevarious ways in which the invention may be practiced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts in a cross-sectional view a “push-pull” reprocessingapparatus of the prior art.

FIG. 2 schematically illustrates a first apparatus and method embodimentof the invention.

FIG. 3 schematically illustrates a second apparatus and methodembodiment of the invention.

FIG. 4 schematically illustrates a third apparatus and method embodimentof the invention.

FIG. 5 schematically illustrates an enlarged view of section X takenfrom FIG. 4.

FIG. 6 schematically illustrates the same enlarged view as FIG. 5 butwith the packaging around the item closed.

FIG. 7 shows a removable baffle plug of the invention.

FIG. 8 schematically illustrates another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The terms “push/pull apparatus,” “push/pull system,”“cleaner/sterilizer,” “push/pull reprocessor,” “reprocessor,” and“reprocessing” as used throughout the specification are meant to besynonymous with the use of a push-pull apparatus (such as the LangfordIC Systems, Inc. Manzi Mach 1) that cleans items (e.g., endoscopes,dental appliances, surgical instruments and the like) by surging fluidback-and-forth upon the accessible surfaces of these items.

The term “bi-directional” means flowing in two directions at once withinthe container of the invention.

As used herein, the term “plasma” is intended to include any portion ofthe gas or vapors which contains electrons, ions, free radicals, and thelike produced as a result of an applied electrical field, including anyaccompanying radiation that might be produced. While radiation in theradio frequency range is most commonly applied, a broad frequency rangemay be used.

Turning to the figures, wherein like numbers designate like features,FIG. 1 depicts a “push-pull” reprocessor of the prior art. An item witha lumen 2 is secured within an opening of a baffle 4 that divides thereprocessor into a first chamber 6 and a second chamber 8. When valves12 and 14 are opened and diaphragms 10A and 10B are simultaneouslyactivated in opposite directions as shown, fluid F flow through andaround the lumen 2. By reversing the direction of the diaphragms 10A and10B in unison, a linear or unidirectional flow is created first one wayand then the other, resulting in a periodic shear force or “scrubbingaction.”

FIG. 2 illustrates in simple schematic form a first embodiment of theinvention. Unlike the linear flow of an initial quantity of “old”sterilant and “push/pull” action created by the apparatus of FIG. 1,this embodiment of the invention bi-directionally flows fresh sterilantinto chamber 18. Thus, for example, mixing tank 16 housing gas plasma isdistributed into chamber 18 via a pump 20 and a bi-directional valve 22.The bi-directional valve 22 conveys plasma into first chamber 24 andsecond chamber 26 at the same time, resulting in a bi-directional flow(indicated by arrows 28A and 28B for inflow and arrows 30A and 30B foroutflow when the pump is reversed) over item 32 and gas permeablepackaging 34. Reversing the pump at desired intervals (e.g., 2 secondsas shown) allows for at least partial evacuation of “old” sterilantwhile introducing fresh or “new” sterilant upon the item 32.

While a chamber 18 containing a baffle 36 is shown in this and otherembodiments, it should be understood that the invention may include achamber with no baffle and into which an item is simply placed orsecured to a clamp or other structure within the chamber. Moreover, theinvention is not limited to gas plasma. Other sterilants may include,for example, ethylene oxide or steam.

In view of the above apparatus and explanation, a method for sterilizingan item encompasses: placing an item 32 within an opening in baffle 36such that the item 32 extends into the first chamber 24 and secondchamber 26, introducing the sterilant into the first and second chamberssuch that the sterilant is made to flow bi-directionally (28A, 28B, 30A,30B) in the chambers, and sterilizing the item while introducing freshsterilant (symbolized by arrows A and B) into the chamber 18 at leastonce during a sterilizing cycle.

The methods of the invention are especially suitable for sterilizationof an item inside a gas-permeable sleeve or packaging 34, because thelack of linear flow or substantial “back and forth” motion reduce thechances that the packaging will be damaged or lost (through, forexample, being impaled by the item 32 or by sliding off as a result ofbeing pulled in one direction). In the embodiment shown in FIG. 2, thisis accomplished by introducing and evacuating the sterilant on each sideof said baffle to provide a continuous bi-directional flow upon item 32.

In another embodiment of the invention pictured in FIG. 3, gas plasmafrom tank 16 is alternately introduced on each side of baffle 36 throughreversing the one-way pump 40 (during periods in which valve 41 isopen). Because sterilant is introduced into only one of chambers 24 or26 at a time, this embodiment initially appears to provide a“uni-directional” flow of fresh sterilant suitable for sterilizing anitem with a lumen. However, as the one-way pump is reversedperiodically, the net effect is have gas flowing within the apparatus 18dynamically to both chambers, with new sterilant being introduced asdesired by opening valve 41.

FIG. 4 illustrates a third embodiment of the invention. Here, thebi-directional flow of sterilant from mixing tank 16 is created by aplurality of pumps 46 and 48. Similar to the one-way pump show in FIG.3, a net bi-directional flow effect is created by alternating betweenpump 46 and 48. Moreover, pumps 46 and 48 can be used at the same timeto create a “pulsing” effect, whereby waves of fresh sterilant areintroduced into chamber 18. The pumps may provide a continuous flow offresh sterilant or may pump the existing sterilant (though the use ofvalves or a bypass (not shown) with the mixing tank 16), with newsterilant being introduced as desired.

In some applications, it may be preferred to dry an item prior tointroducing a sterilant. Thus, drying means 47 is connected to chamber18 to provide heated air. Alternatively, alcohol (e.g., 70% ethanol) ora vacuum can be provided in order to dry item 32.

FIGS. 5 and 6 are greatly enlarged views of section X of FIG. 4. Thus,opening 38 in baffle 36 is more clearly seen. Preferably, the item 32 iscontained in a bag 34 having a sealable end 39 (e.g., such as byadhesive) and is placed into opening 38. Also preferably, the item 32and opening 38 have a “wet fit,” meaning that the friction between theopening and the item is such that fluid (including a gas) can flowbetween different sides of the baffle 36 as shown by arrow AC.

To control the flow between different sides of baffle, and to make thebaffle adaptable to different sized items, one or more removable plugsmay be used with the invention. Turning to FIG. 7, baffle 50 has aremovable plug 52 that is disposed within notch 60 and in sealedarrangement therewith. Thus, plugs with different sized openings 62 maybe utilized for different sized items. Moreover, one or more plugs 52may be removed or filled in to change the flow dynamics between chamberson either side of the baffle.

Also, radio frequency (RF) transmitters and receivers can be used inconjunction with the plug of the invention. Thus, RF device 70 disposedupon plug 52 can be used to identify a compatible item also containing aRF device. For example, RF device 70 could identify a bronchoscopeplaced within the opening 62 of plug 52 and transmit such information tothe operator of the sterilizing apparatus so that a particular programor cycle could be employed.

The pressure present within a push-pull apparatus during reprocessingoperations should be kept substantially constant to avoid collapsing thelumen passage. Moreover, constant pressure during each stroke bestensures that a given flush volume will travel through each lumenedinstrument every time (i.e., the lumen flush volumes are maximized andconsistent for each stroke). However, in view of the variations andcomplexity of lumened instruments, it can be problematic to thoroughlyclean and sterilize them through evacuation of the lumen in bothdirections at a consistent pressure.

Previous reprocessor apparatus, such as the FDA cleared Manzi Mach 1Cleaner Processor System, use a basic control scheme to generate theprocess pressures that result in fluid flow through instrument lumens.This control scheme employs a reciprocating pump operating at a constantspeed. The constant speed control scheme operates the pump at a constantspeed independent of the resulting pressure. Thus, the resultingpressure produced is a product of (i) the volume of fluid (ratio ofchamber fluid to chamber air) and (ii) the baffle restriction thatdivides the chamber into two halves. Since the volume of fluid deliveredinto the chamber can be different from one cycle to the next (this isdue, in part, to the available municipal water pressure supplied and theprecision of the sensors detecting fluid level), different operatingpressures can result.

This range in chamber operating pressures causes the following: Largechamber structure to account for high pressure, reduced fluid flowthrough instrument lumen at low pressure, increased fluid flow throughinstrument lumen at high pressure, and reduced margin on instrumentpressure rating. This constant speed control scheme also produces largetransient pressures and transient pressure drop-outs which occur due tothe fluid dynamics. In other words, there is no active control of theoperating pressure.

Thus, the invention relates to controlling the pressure and amount offluid that is moved from one side of a divided chamber to the other suchthat the fluid is in excess of the total internal volume of the lumenedinstrument(s) being processed. In other words, at least one entirevolume is passed through the lumened instrument(s) being processed forevery directional change in fluid flow or “stroke” of a push-pullinstrument reprocessor. Moreover, each stroke preferably is performed ata constant pressure. Preferably, the total internal volume of a lumenedinstrument is exceeded by at least 1% to better ensure that any effectson flow dynamics caused by changes in diameter or the presence of otherstructures inside the lumen are accounted for.

Thus, the inventor has developed an improvement to the above scheme byactively controlling the operating chamber pressure, thereby producingmore consistent flow through instrument lumens and further reducing thepossibility of instrument damage. The active pressure control schemeimplemented is known as a PID controller (proportional, integral,derivative controller) and can be implemented in hardware or software ora combination. In one embodiment, this improvement is implemented insoftware.

The PID software design relies upon acquiring (reading) pressure valuesfrom two pressure sensors within the reprocessor container and adjustingthe pump rate (speed) so as to cause the pressure to remain within adefined range (target range). The PID controller implements thefollowing:

Proportional (error)=present behaviorP=(requested pressure−actual pressure)/Requested pressureIntegral=past behaviorI=(previous I)+PDerivative=future behaviorD=P−(previous P)

A scaling value is calculated: S=pScale*P+iScale*I+dScale*D

Variable Coefficient Startup Values pScale 0.06 iScale 0.02 dScale −0.02Operational Values pScale 0.04 iScale 0.02 dScale −0.03

The motor speed is adjusted: Target speed=Target speed+S*Target speed

The result of the pressure control algorithm above is that sufficientfluid flow is generated at a controlled (constant or substantiallyconstant) pressure to clean the inside of complex lumened devices ofpractically any length, even with restrictor valves in place or guidewires and other similar obstacles to normal fluid flow. Also, bycompletely evacuating the entire lumen(s) volume every stroke,consistent turbulence is created to clean the outside of the instrumentsand any other non-lumened instruments placed in the same chamber.

Turning to the simplified schematic diagram shown in FIG. 8, areprocessing apparatus 70 is shown that includes a container 72 having afirst chamber 74 and a second chamber 76 that are divided from eachother by a holder 78 to connectorlessly secure a multi-branched lumenedinstrument 80. Ideally, a first portion of the lumened instrument 80lies in the first chamber 74 and a second portion lies in the secondchamber 76.

A liquid medium 82 is contained within both chambers of the containerand is surged back-and-forth by a pumping means 84 that generate astroke by simultaneously increasing fluid pressure within the firstchamber of while decreasing fluid pressure within the second chamber.The pumping means 84 is controlled to displace at least a total internalvolume (V) of the liquid medium 82 through the lumen 86 of instrument 80during each stroke (even when different diameters are present within theinstrument, such as that caused by restrictor valve 88). Thus, forexample, a signal is sent to open valves 88 and 90, whereupon pumpingmeans 84 acts upon diaphragms 92 and 94 to generate a stroke (symbolizedby arrows S) of fluid flow.

The pumping means 84 is controlled to generate a substantially constantpressure P within both chambers of the container 72. Preferably,constant pressure of between 1-29 psi is achieved. Pressure ismaintained according to pressure sensors 96 and 98, which readings fromeach chamber 74, 76 inform the pumping means to vary its motor speed asneeded to ensure that the pressure within each chamber remainssubstantially constant.

The instrument 80 preferably has a “wet fit” within the holder 78 thatallows flow between the device being held and an opening of the holder,thereby creating a turbulent flow 100 to clean the instrument exterior.

The inventor has found that not filling the container 72 to the top withfluid 82 results in better cleaning dynamics, particularly of instrumentexteriors. Thus, preferably the container 72 includes a volume of air102 of between 1-25% at the container top (e.g., 95% fluid, 5% air). Theinventor has tried air volumes of up to 25% with good results.

In view of the apparatus shown in FIG. 8, a method for cleaning and/orsterilizing an instrument having a lumen is provided. First, areprocessor having a back-and-forth motion and including a containerhaving at least one interface that separates the container into two ormore chambers or compartments is provided. Next, an instrument isengaged in a connectorless fashion (i.e., its ends are not coupled witha fitting that shoots fluid within instrument lumen) within an openingin the interface. Then, a flow of a fluid from inside the container isgenerated through the instrument lumen such that fluid corresponding toat least a total internal volume of the lumen is displaced therethroughduring each stroke of the reprocessor. Preferably, the flow exceeds thetotal internal volume of said lumen by at least 1% to ensure fullflow-through of even very complex lumened instruments. Also preferably,the back-and-forth flow of fluid occurs at a substantially constantpressure.

Within the following examples, endoscopes or other medical or dentalinstruments will be used as an example of an item or instrument to bereprocessed. However, the inventor contemplates use of the inventionwith any tubular item, as well as a variety of other items such ascircuit boards, cosmetic instruments, food preparation instruments, andother items in which reliable cleaning and sterility are desirable orrequired.

Example 1

This example utilizes the apparatus shown in FIG. 8. After securing alumened instrument with baffle fittings designed for different sizelumened instruments with one opening of the lumened instrument in oneside of the divided container and the other in the other side of thecontainer. Both chambers of the container are filled to 95% of totalcontainer volume with filtered water containing an effective amount of acleaning agent. The reprocessing apparatus is activated and one side isbrought to a positive pressure and the other to a negative pressure andreversed for 10 minutes by the pumping means. During each stroke of thereprocessor, a pressure sensor in each chamber of the divided containermonitors the pressure and provides feedback used by a controller toadjust the speed of the pumping means such that a substantially constantpressure is maintained at 12.5 psi.

Example 2

The purpose of this test is to document the results of engineeringcharacterization testing performed on a automatic endoscope reprocessor,the Langford I.C. Systems Sterilizer Cleaner (see U.S. Pat. No.5,906,802 for layout and guidance in the use of this reprocessor).Testing was performed on a Cleaner, Sterilizer Breadboard.

The biopsy lumen of three bronchoscopes were loaded with Birmingham Soil(much more than required by FDA test standards) and inoculated withpathogens from an American Society of Test Methods kit. The scopes wereleft sitting for a 24 hour time period to permit some drying. Using thesame Langford I.C. Systems Sterilizer Cleaner liquid-displacementsettings as described, each bronchoscope was subjected to one wash cycleat 10 psi for 5 min with a use concentration of 2.5% of enzymaticcleaner in 10 liters of water. The preferred rate of “liquiddisplacement” (i.e., the back-and-forth liquid cycling rate in theitem-washing chamber of the Sterilizer Cleaner) is 1 gallon per 2seconds.

Upon completion of the cleaning cycle, and if gas plasma use is desired,the bronchoscope is dried for 5 minutes with heated air and thesterilization cycle could take place by flowing gas plasma for 5-30minutes upon the bronchoscope. At least once after the beginning of thesterilizing cycle, fresh gas plasma is pulsed into the chamber to betterensure all surfaces are contacted with active sterilant.

Example 3

A surgical item is placed in a multi-chamber reprocessor and cleaned asabove. The item is then packaged and sealed in a cellulose envelope andtransferred to a chamber separate from the cleaning chamber. Theseparate chamber includes a fluid port to bi-directionally inject gasinto the chamber, with a pump alternately applying positive pressure tothe chamber and a vacuum to evacuate the chamber. The separate chamberincludes radio frequency electrodes to generate the requisite radiofrequency signal. The plasma is generated by evacuating the chamber,introducing a gas or vaporized liquid and turning on the power to theelectrodes. The plasma is generated in the present process in the samemanner as in known prior art plasma sterilization system (e.g., U.S.Pat. No. 4,643,876). The surgical item is exposed from 5-30 minutes tothe plasma.

By way of example, hydrogen peroxide is injected in the form of anaqueous solution of hydrogen peroxide containing from about 3% to 20% byweight of hydrogen peroxide. The concentration of hydrogen peroxidevapor in the chamber may range from 0.05 to 10 mg of hydrogen peroxideper liter of chamber volume. A concentration of 0.125 mg per liter isthe minimum preferred concentration of hydrogen peroxide. Air or aninert gas such as argon, helium, nitrogen, neon or xenon may be added tothe chamber with the hydrogen peroxide to maintain the pressure in thechamber at the desired level. The hydrogen peroxide solution may beinjected in one or more separate injections. Since the hydrogen peroxideis decomposed into non-toxic products during the plasma treatment, noadditional steps are required to remove residual hydrogen peroxide fromthe sterilized object or its packaging prior to use of the object.

Alternatively, if sterilization of a lumened instrument (e.g., abronchoscope) is desired, the above method could be modified for use ina push/pull reprocessor to flow gas plasma upon all accessible surfaces,including the exterior and through the lumen of the scope (before orafter any packaging of the item takes place). “Unidirectional” flow(with occasional reversal of direction) would be employed to urge thegas plasma (or other vapor-phase sterilants, such as steam) toeffectively permeate through the entire lumen.

Various changes in the details and components that have been describedmay be made by those skilled in the art within the principles and scopeof the invention herein described in the specification and defined inthe appended claims. Therefore, while the present invention has beenshown and described herein in what is believed to be the most practicaland preferred embodiments, it is recognized that departures can be madetherefrom within the scope of the invention, which is not to be limitedto the details disclosed herein but is to be accorded the full scope ofthe claims so as to embrace any and all equivalent processes andproducts. All references cited in this application are herebyincorporated by reference herein.

What is claimed is:
 1. A push/pull reprocessor configured to surge aliquid medium back-and-forth through a lumened instrument, comprising:a) a container having a first chamber and a second chamber, saidcontainer having a pressure sensor in each chamber and a holder thatconnectorlessly secures said lumened instrument such that a firstportion of said lumened instrument lies in said first chamber and asecond portion of said lumened instrument lies in said second chamber;and, b) pumping means, wherein said pumping means is configured togenerate, in response to said pressure sensor in each chamber, a strokethat displaces a volume of the liquid medium through said lumenedinstrument secured in said container.
 2. The push/pull reprocessor ofclaim 1, wherein said pumping means is configured to generate asubstantially constant pressure within both chambers of said containerin response to said pressure sensor.
 3. The push/pull reprocessor ofclaim 1, further including a baffle plug that allows flow between thelumened instrument being held and an opening of the plug, therebycreating a turbulent flow to clean the lumened instrument exterior.
 4. Apush/pull reprocessor configured to surge a liquid medium back-and-forththrough a lumened instrument, comprising: a) a container having a firstchamber and a second chamber, said container having a pressure sensor ineach chamber and a holder that connectorlessly secures said lumenedinstrument such that a first portion of said lumened instrument lies insaid first chamber and a second portion of said lumened instrument liesin said second chamber; and, b) pumping means, wherein said pumpingmeans is configured to vary its motor speed as needed in response tosaid pressure sensor in each chamber.
 5. The push/pull reprocessor ofclaim 4, further including a baffle plug that allows flow between thelumened instrument being held and an opening of the plug, therebycreating a turbulent flow to clean the lumened instrument exterior. 6.The push/pull reprocessor of claim 4, wherein said pumping means isconfigured to generate a substantially constant pressure within bothchambers of said container in response to said pressure sensor.